A vacuum-assisted, countergravity casting apparatus using a gas permeable mold is described in the Chandley et al U.S. Pat. No. 4,340,108 issued July 20, 1982 and U.S. Pat. No. 4,606,396 issued Aug. 19, 1986. Typically, the vacuum-assisted, countergravity casting apparatus includes a casting mold having a porous, gas permeable upper mold member (cope) and a lower mold member (drag) sealingly secured together at a common horizontal parting plane, a vacuum box confronting the gas permeable upper mold member and means for immersing the bottom of the lower mold member in an underlying molten metal pool while evacuating the vacuum box to draw the molten metal upwardly through one or more ingate passages in the lower mold member into one or more mold cavities formed between the upper and lower mold members.
Typically, the upper and lower mold members comprise gas permeable, resin-bonded sand mold members which are self-supporting and adhesively secured (glued) together at the common horizontal parting plane to minimize leakage of molten metal at the parting plane.
Improvements in vacuum-assisted, countergravity casting apparatus have eliminated, in some cases, the need to glue such self-supporting upper and lower mold members together at the horizontal parting plane. For example, commonly assigned U.S. Pat. Nos. 4,828,011; 4,809,767; 4,825,933; and 4,858,672 disclose resilient means or rigid means in the vacuum box for pressing the upper mold member into sealing engagement against the lower mold member sans glue at the horizontal parting plane when the mold is mounted to the mouth of the vacuum chamber.
It is an object of the present invention to provide a vacuum-assisted, countergravity casting apparatus wherein a mold stack comprised of a plurality of mold members disposed side-by-side at upright (e.g., vertical) parting planes is disposed atop an underlying mold drag and confronted by a vacuum chamber equipped with cam shaft means therein for holding the mold members in sealed engagement at the parting planes sans glue.
It is still another object of the present invention to provide a vacuum-assisted, countergravity casting apparatus having means for holding a mold stack sealingly engaged against an underlying mold drag while the mold members are held in sealed engagement at upright parting planes between adjacent mold members of the stack.